Русский Русский

Kolesnikov A.S.

Professor of the Department of Life Safety and Environmental Protection, M. Auezov South Kazakhstan University, Kazakhstan

Modeling of an engineering method for calculating the thermal stability of walls with a shielded external surface

https://doi.org/10.58224/2618-7183-2026-9-2-6
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Аннотация
This paper presents a modeling methodology for an engineering calculation of the thermal stability of external walls with a shielded outer surface forming a ventilated façade system. The objective of the study is to develop a practical design tool for assessing the amplitude attenuation and phase shift of the internal surface temperature under daily climatic fluctuations. The method is based on the solution of a one-dimensional transient heat conduction problem for a multilayer structure subjected to periodic climatic effects. The external boundary condition is defined through an equivalent heat transfer formulation that accounts for shortwave solar radiation, longwave radiative exchange between the screen and the ambient environment, convective heat transfer, and possible ventilation of the air cavity. An engineering calculation algorithm is proposed that incorporates the effect of equivalent solar loading and harmonic variations of outdoor air temperature with high amplitudes of environmental and near-wall air layer fluctuations. A numerical procedure is provided for the “screen – air gap” subsystem, followed by the evaluation of internal surface temperature attenuation and transient heat transfer characteristics. Validation against numerical simulations and experimental data demonstrates a deviation not exceeding 5-10%. The results indicate a significant influence of screen reflectivity, air gap ventilation intensity, and wall heat capacity on improving thermal stability and reducing heat gains during the hot season. The proposed enhanced assessment algorithm can be widely applied in design practice, including the selection of thermal insulation thickness for building envelopes in southern regions, the determination of design loads for ventilation and air-conditioning systems, and the evaluation of indoor thermal conditions under intermittent heating and ventilation regimes. The practical significance lies in the ability to optimize façade system parameters with shielded external surfaces to prevent overheating and improve building energy efficiency. The study is conducted within the framework of ensuring thermal safety of buildings in warm climate conditions.
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Experimental evaluation of the thermophysical performance of an adaptive composite wall system under dynamic climatic conditions

https://doi.org/10.58224/2618-7183-2026-9-1-8
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Аннотация
In the sharply continental and hot climate of Kazakhstan, improving building energy efficiency requires adaptive composite envelope systems capable of dynamically responding to external thermal loads. This study provides experimental validation of a newly developed adaptive energy-efficient wall assembly with alternating air channels and a radiant barrier, previously proposed and numerically investigated by the authors. The experiments were conducted in a climatic chamber using a full-scale 3×3 m wall fragment under two operating modes: cold conditions (–14.3 °C) and hot conditions (+26.4 °C with exterior cladding heated up to +46 °C). Interlayer temperatures, heat flux density, and thermal bridging in the bracket zone were measured, and both calculated and effective thermal transmittance resistance values were determined in accordance with regulatory requirements. The experimental results demonstrated strong agreement with numerical simulations: deviations in interlayer temperatures did not exceed 3-7%, while heat flux density differed by 6-9%. The wall configuration Scheme 3/50/75/50 exhibited pronounced adaptive behavior; switching to the ventilation mode during the hot period reduced heat flux density by up to 14% and decreased the temperature gradient within the air channel by an average of 3-5 °C. Under cold conditions, the system increased thermal resistance by up to 18% compared with assemblies without a reflective layer. The obtained effective thermal resistance values comply with the building standards of the Republic of Kazakhstan and confirm the energy efficiency of the wall system for operation in extreme climates. Overall, the experimental validation confirms the reliability of the model and the high practical applicability of the adaptive wall technology. The findings provide a scientifically grounded basis for the development of façade design standards optimized for Central Asian climates and demonstrate the potential for implementation in both new construction and retrofit projects.
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Research on air purification from pulverized large-tonnage tailings of non-ferrous metal ores and the possibility of their use as secondary raw materials

https://doi.org/10.58224/2618-7183-2025-8-6-1
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Аннотация
Pulverized waste (large-tonnage tailings) from the enrichment of non-ferrous metal ores pose a significant environmental threat and a health hazard to the personnel of enterprises and the population of nearby territories. In this regard, this study is devoted to solving the problem of dust suppression with the prospect of subsequent complex tailings processing. The effectiveness of a combined method combining fine-dispersed hydraulic spraying and pulsating ventilation for dust deposition from the tailings of the former Kentau Enrichment Plant (Kentau, Kazakhstan) has been experimentally studied. Laboratory tests were carried out on a specialized stand with monitoring of microclimatic parameters. The results showed that the combined method reduces the dust deposition time by approximately 30% compared to traditional irrigation and by more than two times compared to natural precipitation. Optimal process parameters have been established: nozzle diameter of 10 microns, liquid pressure of 5.4 MPa, air flow velocity of 4 m/s, pulsation frequency of 13 Hz. Based on the X-ray phase analysis of the tailings composition (the total content of zinc compounds is ~3.77%, lead ~4.47%), the economic feasibility of their complex processing is substantiated. A two-stage technology is proposed: preliminary, associated extraction of valuable metals (Zn and Pb) followed by the use of a non-metallized residue rich in oxides of silicon, aluminum and calcium in the production of building materials (cement clinker, ceramics). Thus, effective dust suppression is the first step towards the transition from passive waste storage to active recycling within the framework of the principles of circular economy, which will significantly improve the environmental situation in the region.
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Utilization of serpentinite waste for the production of magnesium compounds

https://doi.org/10.58224/2618-7183-2025-8-5-8
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Аннотация
The article presents the results of research on the complex processing of powdered man-made serpentinite waste formed during the enrichment of chrysotile raw materials in order to obtain high-purity magnesium compounds and assess the potential of their use in the production of building materials. The relevance of the work is due to the need to dispose of accumulated waste and expand the raw material base for the construction industry within the framework of the principles of circular economy. The developed technology includes the stages of acidic leaching of magnesium from PTW with sulfuric acid, neutralization and purification of the solution using thermally activated PTW (TA-PTW) and subsequent precipitation of the target products. It was found that thermal activation of waste at 750 °C leads to dehydroxylation and the formation of highly reactive phases, forsterite and periclase, which significantly increases their sorption activity. The optimal leaching regime is recognized as the use of 0.7 stoichiometrically normal amount of H₂so₄, which makes it possible to extract 82.5% of magnesium from the amount of acid introduced into the solution. The combined use of the initial and thermally activated PTW provides a degree of magnesium extraction of 52.3% of its total content in the system and effective purification of the magnesium sulfate solution from impurities of iron, aluminum, chromium and nickel. Sequential precipitation from the purified solution made it possible to obtain high–purity magnesium hydroxide with a calcium content of 0.0110%, and its subsequent calcination - magnesium oxide with a calcium content of 0.0187%. Special attention is paid to the prospects of practical application of synthesized compounds in the construction industry. It is shown that magnesium sulfate can be used as a modifying additive in cements and as a sealer for magnesia binders. Magnesium hydroxide is an effective flame retardant filler, and magnesium oxide is the main component for the production of flame–resistant and moisture-resistant magnesia binders and plates such as glass-magnesium sheets. Thus, the work demonstrates not only the technical feasibility of highly efficient processing of serpentinite waste, but also the significant resource potential of the resulting magnesium compounds for creating modern building materials with improved performance characteristics.
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Opportunities for environmentally sustainable development of low-carbon technologies in cement production

https://doi.org/10.58224/2618-7183-2025-8-4-1
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Аннотация
In the context of the transition to a low-carbon economy, the development and implementation of environmentally sustainable technologies in cement production is becoming a key priority. Therefore, the development of new binding materials with reduced clinker content or no clinker at all is becoming a key area for reducing the carbon footprint in construction. Use of clinker-free binders, such as geopolymers and various equivalents based on mineral additives, can significantly reduce the carbon footprint of the construction sector in the environment. The most promising and appropriate benchmark is the disposal of industrial waste of aluminosilicate oxide composition with subsequent mechanical and alkaline activation. For the first time, the microstructure of geopolymers based on aspiration cement dust and tuff has been comprehensively studied. The theoretical prerequisite for the creation of a binder system of such a concept is the synthesis of sufficiently strong and resistant to external manifestations of alkali metals, including the structures of frame aluminosilicates with a hidden crystalline structure. The results of a comprehensive study (X-ray phase analysis, scanning electron microscopy, electron dispersion spectrometry, differential thermal analysis and IR spectroscopy) indicate the presence of characteristic hydration reaction products in the geopolymer paste. The following have been identified in the composition of the material: hydrated aluminosilicates; aluminates; silicate groups of sodium and calcium; mineral phases (quartz, calcite); feldspars of the albite-orthoclase series; micaceous components, etc. The data obtained confirm the typical composition characteristic of the processes of structure formation in geopolymer systems. The results obtained on the key results of the conducted studies confirm the high efficiency of the proposed technology and guarantee increased strength and durability of geopolymer concrete.
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Investigation of the stress-strain state of domical masonry vaults

https://doi.org/10.58224/2618-7183-2023-6-6-6
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Аннотация
The results of analytical study of stress-strain state of one of the varieties of vaults erected in various function buildings, i.e. domical masonry vaults covering Orthodox churches, are presented in this article. Due to the ongoing restoration of architectural monuments and religious buildings, as well as in connection with the construction of such facilities as Orthodox churches, the study of stress-strain state of masonry arches and vaults has become especially important in recent decades. Despite the rapid development of new building technologies in the construction of temples, use of these new technologies is shown to be limited and focused on the use of traditional materials. The current level of engineering of building structures with the use of software enables to significantly improve the calculation models and to obtain more reliable results, in particular for the structures under consideration. The domical vault considered herein is formed by wall extensions inclined along a given curve, converging in a horizontal crown under rectangular plan or in one point under square plan. The authors of the article have performed calculations of vaults in both linear and nonlinear formulations, with the results thereunder the forces and deformations of vaults have been analyzed. As a result profiles of vertical pressures and lateral pressures of the vault mounting groups, isopoles of principal stresses, vertical displacements, bending moments and normal forces were calculated.
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